The present invention relates to a multi-directional switching mechanism, more particularly relates to a mechanism for switching on and off activation of one or more load circuits with free choice in the polarity using a ball manually turnable about its center as the major switching element.
In such a machine or mechanical equipment as a crane, a search-light a work machine, it is usually necessary that two or more loads, e.g. driving motors, should be concurrently operated in operational relationship to each other. In order to practice this control, a plurality of switching elements are conventionally used in combination with each other and a single lever or knob is used in order to operate the switching elements simultaneously. In the control of the above-described sense, it is often required that two or more sets of load circuits should be activated with desired combination of polarities of the circuit activation. Thus, the more complicated is the combination of the circuit activation polarities, the more complicated are the construction of the switching unit and operation thereof. Such complexities in the operation and construction of the conventional switching unit should further be amplified by the fact that, in practice, it is in general often required to change the mode of the circuit activation polarities in accordance with the disposition in which the machine is used. That is, provided that a load circuit is provided with an A-terminal and a B-terminal, it will be required under a situation that the circuit should be so biased that the electric current flows from the A-terminal to the B-terminal whereas it will be required under another situation that the circuit should be so biased that the electric current flows from the B-terminal to the A-terminal.
It is therefore the principal object of the present invention to provide a very compact switching mechanism of a very simplified construction which is capable of switching on and off activation of one or more load circuits with freedom in combination of circuit activation polarities via simple manual operation applied on an operating handle.
In accordance with the basic concept of the present invention, a housing defines an internal cavity accommodating a revolving ball which is comprised of a pair of electro-conductive hemispheres and an electro-insulating portion intervening the hemispheres. Each of a pair of terminals of a driving power source circuit is in a constant contact with each of the pair of hemispheres and the ball is associated with at least one load circuit a pair of terminals of which are in contact with the outer surface of the ball at points symmetric to each other with respect to the center of the ball. In the neutral disposition, the terminals of the load circuit are in contact with the electro-insulating portion of the ball and the load circuit is not activated. As the ball is manually turned about 45 degrees about the center thereof, the different terminals of the load circuit come in contact with the different hemispheres of the ball which are differently charged and biased by the driving power source circuit and the load circuit is activated. When the ball is turned about 45 degrees into the opposite direction, the load circuit is activated also but with different polarity.